1. Field of the Invention
In one aspect this invention relates to eye protection for combat personnel. In yet a further aspect, this invention relates to methods of absorbing light beams.
2. Prior Art
Laser technology has become an increasingly important part of modern technological warfare. Lasers are used in aiming devices, range finders, and as countermeasures to defeat various optical aiming and ranging devices.
As part of the development of laser technology, tuneable dye lasers are being developed which are obtained by pumping from other lasers or flash lamps. Such lasers provide high energy pulses and can be made in large variety of different wave lengths. The Ti-Sapphire lasers now being developed can also provide high repetitions of tuneable energy. This means the exact wave length used by an opponent can not be known in advance requiring that any acceptable absorption device be useful over a broad spectrum.
Thus, battlefield personnel are in danger of being exposed to laser radiation either casually or intentionally. With the power densities available from today's technology, serious damage will be done to unprotected eyes and also the optical devices used on combat vehicles. The radiation comes in discrete bursts of energy ranging from a few microjoules up to several joules in intensity and for periods of time from a few nanoseconds to a few microseconds.
To prevent eye damage, any light absorption device must react quickly, on the order of less than 10 picoseconds and absorb light in the range of 400 to 700 nm. Because of the limited time to react, the device must operate passively. A further constraint is the device must transmit light of normal intensity so the user can function in normal light conditions while bursts of high intensity are absorbed. This implies that the absorption material operates in nonlinear manner.
Attempts have been made to develop goggles which are suitable for attenuating the incoming laser beams during the last several years. The attenuation must be to a power level of less than 10 .mu.j which represents an attenuation factor of at least 10,000 since the available lasers can deliver up to several joules of power in the beam with little beam divergence. Partial solutions for beams at a preselected wave length have been achieved; however, there presently exists no protective goggles for personnel which are passive, can absorb a broad spectrum of high intensity beams, and simultaneously allow the user to function under normal light conditions.